The effect of ultraviolet B irradiation compared with oral vitamin D supplementation on the well-being of nursing home residents with dementia: A randomized controlled trial.
We conducted a randomized controlled multi-centre trial to compare the effects of UVB light and vitamin D supplementation (VD) in terms of well-being of nursing home residents with dementia. Participants were randomly assigned to the intervention group (UVB group, n = 41; half-body UVB irradiation, twice weekly over six months, with one standard erythema dose (SED)), or to the control group (VD group, n = 37; 5600 International units (IU) cholecalciferol supplementation once a week).
The main outcome was well-being, measured with the Cohen-Mansfield Agitation Inventory (CMAI) and the Cornell scale for depression in dementia at zero, three, and six months. Secondary outcomes were QUALIDEM quality of life domains and biochemical parameters of bone homeostasis. Intention-to-treat analysis with linear mixed modelling showed no significant between-group differences on agitation (p = 0,431) or depressive symptoms (p = 0.982).